In October last year, the UN issued a landmark report which stated Greenhouse gas emissions must be cut almost in half by 2030 to avert global environmental catastrophe, including the total loss of every coral reef, the disappearance of Arctic ice and the destruction of island communities. Scientists stated that we need keep temperature increases below 1.5°C to avoid the worst effects of global warming. Unless we see a significant move away from fossil fuels to renewable energy and introduce new technology to reverse global warming by removing CO2 from the atmosphere, scientists believe this figure will be exceeded within around 20 years.

This report paints a bleak picture of our future if rapid action is not taken on an individual and corporate level. Organisations have a responsibility to shareholders to look after them both financially and from an environmental perspective so they need to start taking a long-term view and base purchasing decisions on reducing environmental impact. In this way, we can all play a part in contributing to change.

So, from an environmental perspective what needs to be considered when purchasing a UPS?
Operational Efficiency

If we consider a 100kW UPS operating 24 hours per day/365 days per year, every 1% of efficiency loss wastes 1kW every hour. At only 10p/kW hour this equates to £8,760 over a 10 year period and does not include the energy wasted by additional air conditioning. Currently in the UK, more than 60% of this wasted energy comes from the burning of fossil fuels. This is why selecting the most efficient UPS is essential to minimise the carbon footprint.

Beware, operational efficiencies are often stated by manufacturers as being ‘greater than 99%’, however, this 99% efficiency is related to ‘offline’ operation or ‘ecomode’. No datacentre ever operates on this mode as they would be operating on raw mains and only transferring (with a short break in power) to full UPS operation when there is a problem. True online efficiency is the important percentage to compare UPS solutions as this indicates the real UPS operating efficiency.

Right Sizing

From an efficiency perspective, the big challenge is that the IT power requirement in most organizations will change over time. Six-years ago a Comms Room server rack typically required 6kW, today it is likely to require 30kW. So how can the infrastructure be built to meet these dramatically changing demands?

Put simply, a UPS needs to be easily scalable and must always operate at the optimum point on its efficiency curve. A system which is too small will be overloaded, compromising availability while a system which is too large will be inefficient, waste energy and be costly to run. It will also cost more than necessary to maintain due to its size. Scalability and flexibility are therefore essential considerations when purchasing, to ensure the continual ‘right sizing’ of the UPS.

State of the art UPS technology, such as CENTIEL’s 4th Generation modular technology CumulusPower, has a flat efficiency curve for loads above 15% thereby offering the combined benefits of increased flexibility, scalability and lowest running costs.
Battery Technology

Most UPS systems can operate in ambient temperature of 40°C without de-rating, however, VLRA (lead-acid) batteries used in UPS start to degrade at above 20°C. For every 10°C above 20°C, the useful working life of the battery is halved. So, a VRLA battery with a ten-year design life working at 20°C will last five years at 30°C and just over two years at 40°C. In addition to the battery replacement costs and/or the requirement for air conditioning there is the environmental cost of replacing many tonnes of batteries that current legislation classifies as ‘special waste’.

An alternative is Li-ion battery technology.   Li-ion has a higher purchase price but because Li-ion batteries can operate at higher ambient temperatures without degrading the need for air-conditioning is very significantly reduced. In Northern European locations such as the UK this means UPS cooling could be provided by the natural air temperature resulting in significant savings on data centre running costs and, equally importantly, reducing its carbon footprint.

Li-ion batteries also have a much longer useful working life. Five-year design life VRLA batteries operated at 20°C are normally replaced every 3-4 years. With Li-ion this is 13-15 years.


When it comes to UPS purchase there are usually two budgets: one for the capital expenditure and one for maintenance. Traditionally, the employee selecting the cheapest UPS were misguidedly praised for ‘saving money’ but the cheapest UPS are invariably built with the cheapest components which have much higher repair and maintenance costs and are therefore actually ‘costing money’. A top-quality UPS such as CENTEIL’s CumulusPower, using Li-ion batteries will need only one capacitor change 15 years whereas an inferior solution will typically need three capacitor changes plus three sets of replacement VLRA batteries in 15 years.

Commercial UPS installations can learn from Industrial UPS installations where >25 years’ working life is normal for a UPS. It is true that IT technology is changing very rapidly but the same 230V / 50 Hz being used 20 years ago will be the same in 20 years.

So, by using UPS that are engineered to last, commercial organisations can contribute positively to environmental impact by reducing the need for maintenance, replacement parts and scrappage.
Correct Decision Making

The increase in UPS efficiency from 85% in the 1980s to 97% today is a 12% improvement that reduces the UPS’ carbon footprint but purchase decision makers are often still focused only on the bottom line, missing the bigger environmental picture. Of course, increased efficiency and lower total cost of ownership are closely linked and the most environmentally friendly systems enjoy ongoing operating cost savings. However, given a choice, decision makers still take an ill-informed short term view and purchase the lowest cost system thinking they are “saving money” for their company and often contrary to the company’s environmental and sustainability policies. While this behaviour is understandable it is “old school” and needs to change from the top down and employees need to be incentivized and educated help the make the right environmental choices for all our sakes.

Article origonally featured in Networks Europe September 2019

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